Move xfa/fwl/core to xfa/fwl.

xfa/fwl/core/cfwl_evtscroll.h

-// Copyright 2016 PDFium Authors. All rights reserved.
-// Use of this source code is governed by a BSD-style license that can be
-// found in the LICENSE file.
-
-// Original code copyright 2014 Foxit Software Inc. http://www.foxitsoftware.com
-
-#ifndef XFA_FWL_CORE_CFWL_EVTSCROLL_H_
-#define XFA_FWL_CORE_CFWL_EVTSCROLL_H_
-
-#include "xfa/fwl/core/cfwl_event.h"
-
-class CFWL_EvtScroll : public CFWL_Event {
- public:
-  enum class Code {
-    None = 1,
-    Min,
-    Max,
-    PageBackward,
-    PageForward,
-    StepBackward,
-    StepForward,
-    Pos,
-    TrackPos,
-    EndScroll,
-  };
-
-  explicit CFWL_EvtScroll(CFWL_Widget* pSrcTarget);
-  ~CFWL_EvtScroll() override;
-
-  Code m_iScrollCode;
-  FX_FLOAT m_fPos;
-};
-
-#endif  // XFA_FWL_CORE_CFWL_EVTSCROLL_H_